Formation degradation, such as pavement milling, mining, drilling and/or excavating, may be performed using degradation assemblies. In normal use, these assemb lies and auxiliary equipment are subjected to high impact, heat, abrasion, and other environmental factors that wear their mechanical components. Many efforts have been made to improve the service life of these assemblies, including efforts to optimize the method of attachment to the driving mechanism.
One such method is disclosed in U.S. Pat. No. 5,261,499 to Grubb, which is herein incorporated by reference for all that it contains. Grubb discloses a two-piece rotatable cutting bit which comprises a shank and a nose. The shank has an axially forwardly projecting protrusion which carries a resilient spring clip. The protrusion and spring clip are received within a recess in the nose to rotatably attach the nose to the shank.
Another such method is disclosed in U.S. Patent Publication No. 2008/0309146 to Hall, et al., which is herein incorporated by reference for all that it discloses. It discloses, in one aspect, a degradation assembly comprising a shank with a forward end and a rearward end, the rearward end being adapted for attachment to a driving mechanism, with a shield rotatably attached to the forward end of the shank. The shield comprises an underside adapted for rotatable attachment to the shank and an impact tip disposed on an end opposing the underside. A seal is disposed intermediate the shield and the shank.